Investigation of Coffee Instant Premium by Subcritical Water Hydrolysis: Enhance of Caffeine and Antioxidant Contents

The current study observed a basic investigation into instant coffee production through subcritical water (SBW) hydrolysis. A series of SWB research in lab-scale were carried out to optimize the product qualities by adjusting the process parameters such as temperature, solvent amounts, and time for hydrolysis. The caffeine, antioxidant, pH changes, and morphologies of modified and unmodified coffee powder (commercial products) were also evaluated by SEM. The result showed that the optimum conditions were observed for SBW process at 170°C/11.18 ml/20 min with obtained 0.48 mg/ml and 29.40 µg/ml for antioxidant and caffeine, respectively. SEM images represented physical degradation of coffee extracted powder during hydrolysis. Further, the amount of coffee in the blend with mineral amount could be important sources of minerals to the human diet, as evident by EDX analysis. Further, the change of chemistry surface was also confirmed by FTIR. In summary, flow-through SBW hydrolysis of coffee extract promises for enhance caffeine and antioxidant.